Fused thiophenes, methods for making fused thiophenes, and uses thereof

ABSTRACT

Described herein are compositions including heterocyclic organic compounds such as fused thiophene compounds, methods for making them, and uses thereof.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a divisional application of U.S. applicationSer. No. 11/711,924, now U.S. Pat. No. 7,838,623, filed on Feb. 28,2007, which is a continuation-in-part of Int'l Appl. No. PCT/US05/32759,filed on Sep. 13, 2005, which claims the benefit of U.S. Prov. Appl. No.60/609,881, filed Sep. 14, 2004, all of which are hereby incorporated byreference in their entirety for all purposes.

BACKGROUND

1. Field of the Invention

Described herein are compositions including heterocyclic organiccompounds. More specifically, described herein are fused thiophenecompounds, methods for making them, and uses thereof.

2. Technical Background

Highly conjugated organic materials are currently the focus of greatresearch activity, chiefly due to their interesting electronic andoptoelectronic properties. They are being investigated for use in avariety of applications, including field effect transistors (FETs),thin-film transistors (TFTs), organic light-emitting diodes (OLEDs),electro-optic (EO) applications, as conductive materials, as two photonmixing materials, as organic semiconductors, and as non-linear optical(NLO) materials. Highly conjugated organic materials may find utility indevices such as RFID tags, electroluminescent devices in flat paneldisplays, and in photovoltaic and sensor devices.

Materials such as pentacene, poly(thiophene),poly(thiophene-co-vinylene), poly(p-phenylene-co-vinylene) andoligo(3-hexylthiophene) have been intensively studied for use in variouselectronic and optoelectronic applications. More recently, fusedthiophene compounds have been found to have advantageous properties. Forexample, bisdithieno[3,2-b:2′,3′-d]thiophene (1, j=2) has been found toefficiently π-stack in the solid state, possesses high mobility (up to0.05 cm²/V·s), and has a high on/off ratio (up to 10⁸). Oligomers andpolymers of fused thiophenes, such as oligo- orpoly(thieno[3,2-b]thiophene (2) and oligo- orpoly(dithieno[3,2-b:2′-3′-d]thiophene) (1)

have also been suggested for use in electronic and optoelectronicdevices, and have been shown to have acceptable conductivities andnon-linear optical properties. Unsubstituted fused thiophene-basedmaterials tend to suffer from low solubility, marginal processabilityand oxidative instability. Thus, there remains a need for fusedthiophene-based materials having acceptable solubility, processabilityand oxidative stability.

SUMMARY

Described herein are compositions including heterocyclic organiccompounds such as fused thiophene compounds, methods for making them,and uses thereof. The compositions and methods described herein possessa number of advantages over prior art compositions and methods. Forexample, the fused thiophene compositions described herein can be madeto be more soluble and processable than the analogous unsubstitutedthiophene compositions. Polymers and oligomers including the fusedthiophene moieties described herein can be made to be processable usingconventional spin-coating operations. Further, the compositionsdescribed herein can be made with substantially no β-H content, greatlyimproving the oxidative stability of the compositions.

Additional features and advantages will be set forth in the detaileddescription which follows, and in part will be readily apparent to thoseskilled in the art from the description or recognized by practicing theinvention as described in the written description and claims hereof, aswell as in the appended drawings.

It is to be understood that both the foregoing general description andthe following detailed description are merely exemplary, and areintended to provide an overview or framework for understanding thenature and character of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are included to provide a furtherunderstanding of the invention, and are incorporated in and constitute apart of this specification. The drawings are not necessarily to scale,and sizes of various elements may be distorted for clarity. For example,for the sake of clarity, not all distal ends of the optical fibers areshown in the drawings. The drawings illustrate one or more embodiment(s)of the invention and together with the description serve to explain theprinciples and operation of the invention.

FIG. 1 is a reaction scheme showing a method for making aβ″-R-substituted fused thiophene moieties.

FIG. 2 is a reaction scheme showing a method for making anα-(R-acyl)-β-carboxymethylthio thiophene moiety.

FIG. 3 is a reaction scheme showing a method for making anα′-hydro-β″-R-substituted fused thiophene moiety.

FIG. 4 is a reaction scheme in which there is a simultaneous cyclizationon both sides of a thiophene moiety.

FIG. 5 is a reaction scheme showing an alternative method for making anα,α′-bis(R-acyl)-β,β′-bis(carboxymethylthio)thiophene moiety.

FIG. 6 is a reaction scheme showing a method for making a five-ringfused thiophene.

FIG. 7 is a reaction scheme showing a method for making polycyclicβ-R-substituted-β′-bromo thiophene moieties.

FIG. 8 is a reaction scheme showing a method for makingβ-R-substituted-β′-bromo thiophene compounds.

FIG. 9 is reaction scheme showing a method for making monosubstitutedfused thiophene moieties.

FIG. 10 is a reaction scheme showing the synthesis of3,6-dihexylthieno[3,2-b]thiophene and 3,6-didecylthieno[3,2-b]thiopheneaccording to Example 1.

FIG. 11 is a reaction scheme showing the synthesis of3-hexylthieno[3,2-b]thiophene according to Example 2.

FIG. 12 is a reaction scheme showing the synthesis of3,6-didecylthieno[3,2-b]thiophene and3,6-didecylthieno[3,2-b]thiophene-4,4-dioxide according to Example 3.

FIG. 13 is a reaction scheme showing the synthesis of3,7-didecylthieno[3,2-b]thieno[2′,3′:4,5]thieno[2,3-d]thiopheneaccording to Example 4.

FIG. 14 is a reaction scheme showing the failed synthesis ofβ-hexyl-substituted thieno[2,3-d]thiophene according to conventionalmethodologies as described in Example 5.

FIGS. 15A and B are reaction schemes for the synthesis 2-2 and 3-3dimers and 5- and 7-ring systems according to Example 7.

FIG. 16 is a reaction scheme for the synthesis of a seven-ringtetraalkylsubstituted thienothiophene according to Example 8.

FIG. 17 is a reaction scheme for the synthesis of a nine-ringtetraalkylsubstituted thienothiophene according to Example 8.

FIG. 18 is a reaction scheme for producing fused thiophene copolymers.

FIGS. 19A and B show structures of different fused thiophene copolymersproduced by the methods described herein.

DETAILED DESCRIPTION

Before the present materials, articles, and/or methods are disclosed anddescribed, it is to be understood that the aspects described below arenot limited to specific compounds, synthetic methods, or uses as suchmay, of course, vary. It is also to be understood that the terminologyused herein is for the purpose of describing particular aspects only andis not intended to be limiting.

In this specification and in the claims that follow, reference will bemade to a number of terms that shall be defined to have the followingmeanings:

Throughout this specification, unless the context requires otherwise,the word “comprise,” or variations such as “comprises” or “comprising,”will be understood to imply the inclusion of a stated integer or step orgroup of integers or steps but not the exclusion of any other integer orstep or group of integers or steps.

It must be noted that, as used in the specification and the appendedclaims, the singular forms “a,” “an” and “the” include plural referentsunless the context clearly dictates otherwise. Thus, for example,reference to “a pharmaceutical carrier” includes mixtures of two or moresuch carriers, and the like.

“Optional” or “optionally” means that the subsequently described eventor circumstance can or cannot occur, and that the description includesinstances where the event or circumstance occurs and instances where itdoes not.

Ranges may be expressed herein as from “about” one particular value,and/or to “about” another particular value. When such a range isexpressed, another aspect includes from the one particular value and/orto the other particular value. Similarly, when values are expressed asapproximations, by use of the antecedent “about,” it will be understoodthat the particular value forms another aspect. It will be furtherunderstood that the endpoints of each of the ranges are significant bothin relation to the other endpoint, and independently of the otherendpoint.

A weight percent of a component, unless specifically stated to thecontrary, is based on the total weight of the formulation or compositionin which the component is included.

The term “alkyl group” as used herein is a branched or unbranchedsaturated hydrocarbon group of 1 to 40 carbon atoms, such as methyl,ethyl, n-propyl, isopropyl, n-butyl, isobutyl, t-butyl, pentyl, hexyl,heptyl, octyl, decyl, or tetradecyl, and the like. The alkyl group canbe substituted or unsubstituted. The term “unsubstituted alkyl group” isdefined herein as an alkyl group composed of just carbon and hydrogen.The term “substituted alkyl group” is defined herein as an alkyl groupwith one or more hydrogen atoms substituted with a group including, butnot limited to, an aryl group, cycloalkyl group, aralkyl group, analkenyl group, an alkynyl group, an amino group, an ester, an aldehyde,a hydroxyl group, an alkoxy group, a thiol group, a thioalkyl group, ora halide, an acyl halide, an acrylate, or a vinyl ether. For example,the alkyl groups can be an alkyl hydroxy group, where any of thehydrogen atoms of the alkyl group are substituted with a hydroxyl group.

The term “alkyl group” as defined herein also includes cycloalkylgroups. The term “cycloalkyl group” as used herein is a non-aromaticcarbon-based ring composed of at least three carbon atoms. Examples ofcycloalkyl groups include, but are not limited to, cyclopropyl,cyclobutyl, cyclopentyl, cyclohexyl, etc. The term cycloalkyl group alsoincludes a heterocycloalkyl group, where at least one of the carbonatoms of the ring is substituted with a heteroatom such as, but notlimited to, nitrogen, oxygen, sulphur, or phosphorus.

The term “aryl group” as used herein is any carbon-based aromatic groupincluding, but not limited to, benzene, naphthalene, etc. The term “arylgroup” also includes “heteroaryl group,” which is defined as an arylgroup that has at least one heteroatom incorporated within the ring ofthe aromatic group. Examples of heteroatoms include, but are not limitedto, nitrogen, oxygen, sulfur, and phosphorus. The aryl group can besubstituted or unsubstituted. The aryl group can be substituted with oneor more groups including, but not limited to, alkyl, alkynyl, alkenyl,aryl, halide, nitro, amino, ester, ketone, aldehyde, hydroxy, carboxylicacid, or alkoxy as defined herein.

The term “aralkyl” as used herein is an aryl group having an alkyl groupas defined above attached to the aryl group. An example of an aralkylgroup is a benzyl group.

The term “alkenyl group” is defined as a branched or unbranchedhydrocarbon group of 2 to 40 carbon atoms and structural formulacontaining at least one carbon-carbon double bond.

The term “alkynyl group” is defined as a branched or unbranchedhydrocarbon group of 2 to 40 carbon atoms and a structural formulacontaining at least one carbon-carbon triple bond.

Disclosed are compounds, compositions, and components that can be usedfor, can be used in conjunction with, can be used in preparation for, orare products of the disclosed methods and compositions. These and othermaterials are disclosed herein, and it is understood that whencombinations, subsets, interactions, groups, etc. of these materials aredisclosed that while specific reference of each various individual andcollective combinations and permutation of these compounds may not beexplicitly disclosed, each is specifically contemplated and describedherein. Thus, if a class of molecules A, B, and C are disclosed as wellas a class of molecules D, E, and F and an example of a combinationmolecule, A-D is disclosed, then even if each is not individuallyrecited, each is individually and collectively contemplated. Thus, inthis example, each of the combinations A-E, A-F, B-D, B-E, B-F, C-D,C-E, and C-F are specifically contemplated and should be considereddisclosed from disclosure of A, B, and C; D, E, and F; and the examplecombination A-D. Likewise, any subset or combination of these is alsospecifically contemplated and disclosed. Thus, for example, thesub-group of A-E, B-F, and C-E are specifically contemplated and shouldbe considered disclosed from disclosure of A, B, and C; D, E, and F; andthe example combination A-D. This concept applies to all aspects of thisdisclosure including, but not limited to, steps in methods of making andusing the disclosed compositions. Thus, if there are a variety ofadditional steps that can be performed it is understood that each ofthese additional steps can be performed with any specific embodiment orcombination of embodiments of the disclosed methods, and that each suchcombination is specifically contemplated and should be considereddisclosed.

In one aspect, described herein are compositions comprising at least onefused thiophene moiety comprising the formula 3 or 4

In another aspect, the composition comprising at least one moietycomprising the formula 3′ or 4′

wherein n is an integer greater than zero; m is no less than one; o isno less than one; x is greater than or equal to one; R₁ and R₂ are,independently, hydrogen or an alkyl group, wherein at least one of R₁and R₂ is an alkyl group, and Ar is an aryl group, wherein n is not one.

In one aspect, with respect to structures 3, 3′, 4, and 4′, n is aninteger greater than zero; m is no less than one; R₁ and R₂ are,independently, hydrogen or an alkyl group, wherein at least one of R₁and R₂ is an alkyl group, and wherein n is not 1. As used herein, thefused thiophene ring system of a fused thiophene moiety is theheterocyclic core of the moiety, and does not include the α-substituentsand the β-substituents (e.g. R₁ and R₂) bound to the fused thiophenering system. For example, the fused thiophene ring systems of structures3 and 4 having n=1 are shown below as structures 5 and 6, respectively.

The fused thiophene moieties described herein can have any number offused rings. For example, the fused thiophene moieties can be bicyclic(3 and 3′, n=1); tricyclic (4 and 4′, n=1); tetracyclic (3 and 3′, n=2);pentacyclic (4 and 4′, n=2), hexacyclic (3 and 3′, n=3); or heptacyclic(4 and 4′, n=3). The methods described herein permit the construction offused thiophene moieties having any desired number of rings. In oneaspect, n is 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, or 15. Inother aspects, the fused thiophene moiety can be tricyclic or greater(i.e., 4 or 4′, n 1; or 3 or 3′, n≧2).

The fused thiophene moieties described herein are substituted at atleast one of the β-positions of the fused thiophene ring system with analkyl group. As used herein, an α-position of a fused thiophene ringsystem is a non-fused carbon center that is directly adjacent to thesulfur of a fused thiophene, while a β-position is a non-fused carboncenter that is separated from the sulfur of the fused thiophene by anα-position. In the structures 3, 3′, 4, and 4′, the α-positions areshown as being connected to the rest of the composition, while theβ-positions are substituted with R₁ and R₂.

In one aspect, at least one of R₁ and R₂ is an alkyl group. Previously,there have been no methods for producing fused thiophene moieties ofstructures 3, 3′, 4, and 4′ having alkyl substitution at the β-positionsof the fused thiophene ring system. As described in more detail in theExamples, below, methods conventionally used to alkylate simple unfusedthiophenes fail when used in attempts to alkylate fused thiophene ringsystems. In one aspect, described herein are methods for making fusedthiophene moieties having large alkyl substitution at the β-positions ofthe fused thiophene ring system.

In one aspect, R₁ and R₂ can be a variety of substituted orunsubstituted alkyl groups. For example, at least one of R₁ or R₂ is anunsubstituted alkyl group. In this aspect, the unsubstituted alkyl groupcan be a straight-chain alkyl group (e.g. methyl, ethyl, propyl, butyl,pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl orhexadecyl), a branched alkyl group (e.g. sec-butyl, neo-pentyl,4-methylpentyl), or a substituted or unsubstituted cycloalkyl group(e.g. cyclopentyl, cyclohexyl). In another aspect, at least one of R₁ orR₂ is an alkyl group, itself at least four carbons in size, which issubstituted. In a further aspect, substitution of the alkyl group isseparated from the fused thiophene ring system by at least two carbons.In one aspect, R₁ and/or R₂ can be substituted with an aryl group,cycloalkyl group, aralkyl group, an alkenyl group, an alkynyl group, anamino group, an ester, an aldehyde, a hydroxyl group, an alkoxy group, athiol group, a thioalkyl group, or a halide, acyl halide, an acrylate,or a vinyl ether. Examples of substituted alkyl groups include, but arenot limited to, 6-hydroxyhexyl and 3-phenylbutyl. The selection of R₁and R₂ will depend on the end use of the fused thiophenemoiety-containing composition. The methods described herein permit thesynthesis of fused thiophene moieties having a wide variety of R₁ and R₂substituents. Any functionality on a substituted alkyl group can beprotected in order to survive subsequent reaction steps.

Unsubstituted fused thiophene ring systems (i.e., no substitution at theα- or β-positions) tend to be relatively insoluble. Thus, in one aspect,R₁ and R₂ can be an alkyl group having at least six carbons in size. Forexample, the alkyl group can have the formula C_(k)H_(2k+1), where k isan integer greater than or equal to six.

In certain aspects, the fused thiophene ring system is substituted atboth β-positions, so that there are no β-hydrogens on the ring system.For example, in one aspect, neither R₁ nor R₂ in structures 3, 3′, 4,and 4′ is H. Such moieties can be incorporated in oligomers and polymershaving substantially no β-hydrogen content, and will have increasedoxidative stability. For example, the molar ratio of β-hydrogen to fusedthiophene ring system can be less than about ⅙, 1/7, ⅛, 1/9, or 1/10. Ina further aspect, one or both of R₁ and R₂ can be an alkyl group. In oneaspect, R₁ and R₂ are identical alkyl groups. When R₁ and R₂ areidentical, regioregular polymers can be easily constructed because theproblems of regioselectivity (i.e. head-to-tail vs. head-to-headcoupling) of polymerization reactions disappear. In other aspects, R₁and R₂ may also be different. For example, R₁ can be at least fourcarbons in size, with R₂ being less than four carbons in size (e.g., amethyl group). Alternatively, in another aspect, both R¹ and R² can beat least four carbons in size.

With respect to moieties 3′ and 4′, an aryl group (Ar) is attached tothe α-position of the fused thiophene moiety. The term “aryl group” asused herein is any carbon-based aromatic group. The aryl groups caninclude fused aromatic groups such as, for example, naphthalene,anthracene, and the like. The term “aromatic” also includes “heteroarylgroup,” which is defined as an aromatic group that has at least oneheteroatom incorporated within the ring of the aromatic group. Examplesof heteroatoms include, but are not limited to, nitrogen, oxygen,sulfur, and phosphorus. The aryl group can be substituted orunsubstituted. The aryl group can be substituted with one or more groupsincluding, but not limited to, alkyl, alkynyl, alkenyl, aryl, halide,nitro, amino, ester, ketone, aldehyde, hydroxy, carboxylic acid, oralkoxy.

In one aspect, wherein Ar comprises one or more unfused thiophenegroups, one or more fused thiophene groups, or a combination of unfusedand fused thiophene groups. For example, the moiety comprises theformula 200 or 201

wherein o is 1, 2, or 3, and R₃ and R₄ are, independently, hydrogen oran alkyl group. In this aspect, Ar is one or more substituted orunsubstituted thiophene groups. In one aspect, n is 2, 3, or 4, and mis 1. In another aspect, n is 2, 3, or 4; m is one; and o is 1, 2, or 3.In the case when Ar is a fused thiophene, it is contemplated that thefused thiophene can be one fused thiophene group or two or more fusedthiophene groups. When Ar is two or more fused thiophene groups, thefused thiophene groups can be the same or different. For example, Ar canbe a bis-fused thiophene covalently bonded to a tris-fused thiophene. Inother aspects, Ar can be one or more substituted or unsubstitutedthiophene groups bonded to a substituted or unsubstituted fusedthiophene group.

The fused thiophene moieties of structures 3 and 4 can exist as simplemonomeric fused thiophenes, or can be incorporated into more complexcompounds, oligomers or polymers. For example, the fused thiophenemoieties described herein can be incorporated in simple fused thiophenemonomers having the formulae 7 and 8,

wherein n is an integer greater than zero; R₁ and R₂ are, independently,hydrogen or an alkyl group, and Q is, independently, hydrogen, asubstituted or unsubstituted alkyl group (e.g., an alkyl hydroxy group),a carboxylic acid, an acyl halide, an ester, an aldehyde, a ketone, ahydroxyl group, a thiol group or alkyl substituted thiol group, analkoxy group, an acrylate group, an amino group, a vinyl ether, or ahalide. In one aspect, each Q in 7 and 8 is bromide. In certain aspects,monomers having structures 7 and 8 can be used to make fused thiopheneoligomers and polymers, as described below.

The fused thiophene monomers 7 and 8 can be incorporated in oligomersand polymers having conjugated homo-oligomeric or homopolymeric blocksof the fused thiophene moieties to produce polymers having the fusedthiophene moieties 3, 3′, 4, or 4′. For example, according to oneembodiment, an oligomer or polymer includes a fused thiophene ofstructure 3, 3′, 4, or 4′ in which m is greater than 1. In furtherembodiments, m is at least about four. In another aspect, when thepolymer is a homopolymer, m is at least about 10. In this aspect, it iscontemplated that the monomers 7 or 8 can be polymerized to produce ahomopolymer composed of residues having the formula 3 or 4. In otheraspects, m is from 1 to 10,000, 1 to 9,000, 1 to 8,000, 1 to 7,000, 1 to6,000, 1 to 5,000, 1 to 4,000, 1 to 3,000, 1 to 2,000, 1 to 1,000, 1 to500, 1 to 250, 1 to 100, 1 to 50, 1 to 25, or 1 to 10.

In other aspects, the fused thiophene monomers described herein (e.g., 7and 8) can be incorporated into conjugated copolymers with otheraromatic or unsaturated moieties. For example, the fused thiophenemonomers 7 and 8 can be copolymerized with other substituted orunsubstituted fused thiophene moieties to form a conjugated fusedthiophene polymer or oligomer. Alternatively, the fused thiophenemonomers 7 and 8 can be copolymerized with substituted or unsubstitutedthiophenes to form thiophene/fused thiophene polymers or oligomers. Thefused thiophene monomers 7 and 8 can also be copolymerized with othermoieties commonly used in conjugated polymers, such as vinylene,phenylene, or other arylene or heteroarylene moieties.

The fused thiophene moieties described herein can be incorporated into awide variety of other types of polymers. For example, the fusedthiophenes having the formula 7 and 8 can be incorporated into the mainchain of a polymer such as, for example, a polyester, a polyurethane, apolyether, a polyamide, a polycarbonate, or a polyketone; and in theside chain of a polymer such as, for example, a polyacrylate, apolymethacrylate, or a poly(vinyl ether). It is contemplated that thefused thiophenes having the formula 7 and 8 can be modified withreactive groups (e.g., acyl chloride, alcohol, acrylate, amine, vinylether) that will permit the incorporation of the monomer into thepolymer. For example, R¹, R², and/or Q can be modified with suchreactive groups.

In one aspect, compounds comprising the moiety 3′ or 4′ can be producedby reacting a compound comprising the formula 210 or 220

wherein n is an integer greater than or equal to two; m is no less thanone; R₁ and R₂ are, independently, hydrogen or an alkyl group, whereinat least one of R₁ and R₂ is an alkyl group,with a compound having the formula (R⁵)₃Sn—Ar—Sn(R⁵)₃, wherein Arcomprises an aryl group and R⁵ is an alkyl group. In this aspect, thedibromo-fused thiophene is coupled with a bis-stannyl aryl group. Thecoupling reaction is generally performed in the presence of a catalystssuch as, for example Pd(0). FIG. 18 depicts one aspect of this method,where the dibromo-fused thiophene (formula 210, n=3, m=1) is coupledwith 2,5′-distannyltrimethyl-bithiophene in the presence of Pd(PPh₃)₄ toproduce a copolymer. Using this methodology, it is possible to produceco-polymers such as block co-polymers, where the value of m and o in 3′and 4′ can vary depending upon the desired molecular weight of thecopolymer.

In another aspect, the fused thiophenes described herein can also beincorporated in donor-acceptor chromophores, such as those commonly usedin polymeric electro-optic materials. For example, the fused thiophenemoieties of structures 3 and 4 can be incorporated into a donor-acceptorchromophore having the structure 9 or 10:

where D is an electron donating group, and A is an electron acceptinggroup. Donor-acceptor chromophores are described in more detail in U.S.Pat. Nos. 6,584,266; 6,514,434; 6,448,416; 6,444,830; and 6,393,190,each of which is hereby incorporated herein by reference in itsentirety. In one aspect, the fused thiophene having the formula 7 or 8can be reacted with an electron donating group and electron acceptinggroup to produce compounds having the formula 9 and 10, respectively.

In various aspects, the compositions described herein have asufficiently high concentration of the fused thiophene moieties ofstructures 3 or 4 to yield a desired electronic or optoelectronicproperty to the composition. For example, the compositions have at leastone fused thiophene moiety of structures 3 or 4 in a total concentrationof at least 1 wt %. In a further aspect, the compositions describedherein have at least one fused thiophene moiety of structures 3 or 4 ina total concentration of at least 3 wt %. In additional aspects, thecomposition has at least one fused thiophene moiety of structures 3 or 4in higher total concentrations of, for example, at least 10 wt % or atleast 50 wt %. Due to the presence of an alkyl group at the β-positionof the fused thiophene ring, the compositions can have higherconcentrations of fused thiophene moieties yet remain soluble andprocessable.

The compositions described herein (monomers, oligomers, polymers) can beused to make a wide variety of devices. For example, the device can be afused thiophene moiety-containing composition configured in anelectronic, optoelectronic, or nonlinear optical device. Thecompositions described herein can also be used in field effecttransistors (FETs), thin-film transistors (TFTs), organic light-emittingdiodes (OLEDs), PLED applications, electro-optic (EO) applications, asconductive materials, as two photon mixing materials, as organicsemiconductors, as non-linear optical (NLO) materials, as RFID tags, aselectroluminescent devices in flat panel displays, in photovoltaicdevices, and as chemical or biological sensors.

The polymers comprising the fused thiophene moieties described herein(3, 3′, 4, and 4′) possess enhanced packing ability and thermalstability. The polymers also display liquid crystalline phases overcertain temperature ranges. The liquid crystalline properties can easilybe tuned by changing the length of the alkyl groups R₁ and R₂. Thepolymers also have good solubility in organic solvents such as, forexample, THF, toluene, chlorobenzene, which permits the casting of thinfilms using techniques known in the art.

Described herein are methods for making fused thiophene compounds. Inone aspect, the method for making a β″-R-substituted fused thiophenemoiety comprises the steps of:

-   -   (i) providing an α-hydro β-bromo thiophene moiety;    -   (ii) converting the α-hydro β-bromo thiophene moiety to an        α-(R-acyl)-β-carboxymethylthio thiophene moiety by acylating the        thiophene moiety at the α-position with an R-acyl moiety, where        R is an alkyl group having at least four carbons,    -   (iii) substituting the β-bromide with a 2-mercaptoacetate;    -   (iv) cyclizing the α-(R-acyl)-β-carboxymethylthio thiophene        moiety to form an α″-carboxy-β″-R-substituted fused thiophene        moiety; and    -   (v) decarboxylating the α″-carboxy β″-R-substituted fused        thiophene moiety to form the β″-R-substituted fused thiophene        moiety.

In one aspect, a method for making a β″-R-substituted fused thiophenecompound is shown in the reaction scheme of FIG. 1. First, anα-hydro-β-bromo thiophene moiety 11 is provided. The α-hydro-β-bromothiophene moiety 11 can be a simple unfused thiophene, as shown instructures 12 and 13 below. Structure 12 is an unsubstituted unfusedα-hydro-β-bromo thiophene, which upon ring fusion producethienothiophene 14 having a single 13 substitution. Structure 13 is R′substituted at the β′ center (i.e., a α-hydro-β-bromo-β′-R′-substitutedthiophene), which upon ring fusion produces a doubly β-substitutedthienothiopene 15.

The α-hydro-β-bromo thiophene moiety is then converted to anα-(R-acyl)-β-carboxymethylthio thiophene moiety 16. As used herein, thename “R-acyl” is meant to denote radical structure 17 below, and thename “carboxymethylthio” is meant to denote radical structure 18 below,where Z is the terminus of the carboxylate (which may be, e.g., H,substituted alkyl, unsubstituted alkyl). In one aspect, Z is H, methyl,ethyl or propyl. The reaction scheme shown in FIG. 2 and described inmore detail in the examples can be used to effect the conversion of theα-hydro-β-bromo thiophene moiety 11 to theα-(R-acyl)-β-carboxymethylthio thiophene moiety 16. The α-hydro-β-bromothiophene moiety is first acylated at the α-position with a R-acylmoiety using RCOCl and AlCl₃, where R is an alkyl group having at leastfour carbons. The acylated product is reacted with the 2-mercaptoacetateHSCH₂COOZ to yield the α-(R-acyl)-β-carboxymethylthio thiophene moiety16. While in the reaction scheme of FIG. 2, the R-acylation is performedfirst, in certain cases the reactions can be performed in the oppositeorder.

The α-(R-acyl)-β-carboxymethylthio thiophene moiety 16 is then cyclized(e.g., via a base-catalyzed condensation, often under the sameconditions as the reaction with the 2-mercaptoacetate) to yield anα″-carboxy-β″-R-substituted fused thiophene moiety 19, which isdecarboxylated to form the β″-R-substituted fused thiophene moiety 20,where R is an alkyl group having at least four carbons.

If the α-hydro-β-bromo thiophene moiety 11 of the reaction scheme ofFIG. 2 has a hydrogen at its α′-position, then the acylation step maynot be specific to the α-position. For example, as shown in the reactionscheme of FIG. 3, α,α′-dihydro-β-bromo thiophene moiety 21 is acylatedand reacted with a 2-mercaptoacetate, forming a mixture of productsincluding the desired α-(R-acyl)-α′-hydro-β-carboxymethylthio thiophenemoiety 22, as well as the undesired regioisomericα′-hydro-α-(R-acyl)-β-carboxymethylthio thiophene moiety 23. Sincemoieties 22 and 23 are likely to be separable from one another, thecyclization step on the mixture can be performed; regioisomer 22 willcyclize to form α′-hydro-α″-carboxy-β″-R-substituted fused thiophenemoiety 24, while regioisomer 23 will not cyclize. The fused thiophenemoiety 24 can now be separated from uncyclized regioisomer 23, and canbe decarboxylated to yield α′-hydro-β″-R-substituted fused thiophenemoiety 25.

In other aspects, the methods described in the reaction schemes of FIGS.2 and 3 can be used to make a variety of fused thiophene compounds. Forexample, if the α-hydro-β-bromo thiophene moiety 11 of the reactionscheme of FIG. 2 is an α-hydro-β-bromo-β′-R′-substituted thiophenemoiety 13, then the end product fused thiophene will be aβ″-R-substituted-β′-R′-substituted fused thiophene moiety 15. R′ can be,for example, an alkyl group having at least four carbons, and can be thesame as or different from R. R′ can also be any other desiredsubstitution, including an alkyl group having less than four carbons.

The general cyclization method of the reaction scheme of FIG. 2 can beused to simultaneously perform cyclization on both sides of a thiophenemoiety, as shown in the reaction scheme of FIG. 4. Anα,α′-dihydro-β,β′-dibromo thiophene moiety 26 is used as the startingmaterial. While in the reaction scheme of FIG. 4 theα,α′-dihydro-β,β′-dibromo thiophene moiety 26 is shown as a monocyclicsimple thiophene, the skilled artisan will understand that thiophenemoiety 26 can have fused thiophenes (such as thieno[3,2-b]thiophene orbisdithieno[3,2-b:2′-3′-d]thiophene) as its fused thiophene ring system.Thiophene moiety 26 is acylated (for example, as described above usingFriedel-Crafts chemistry) at both the α and α′ positions, and is reactedwith a 2-mercaptoacetate at both the β and β′ positions to yield anα,α′-bis(R-acyl)-β,β′-bis(carboxymethylthio) thiophene moiety 27, whichis cyclized (forming 28) and decarboxylated to formβ″,β′″-bis(R-substituted) fused thiophene moiety 29, which has a fusedthiophene ring system that is two rings larger than that of the startingmaterial thiophene moiety 26. Alternatively, theα,α′-dihydro-β,β′-dibromo thiophene moiety 26 can be subjected to afirst series of R-acylation/reaction with2-mercaptoacetate/cyclization/decarboxylation reactions, then to asecond series of reactions with a different R′ group in the acylationstep to provide a β″-(R-substituted)-β′″-(R′-substituted) fusedthiophene moiety in which R and R′ are different from one another.

The reaction scheme of FIG. 5 shows an alternative way to make anα,α′-bis(R-acyl)-β,β′-bis(carboxymethylthio) thiophene moiety 27. Anα,α′,β,β′-tetrabromo thiophene moiety 30 is lithiated (selectively atthe α-positions) and reacted with an aldehyde RCHO to form diol 31,which is oxidized to form α,α′-bis(R-acyl)-β,β′-dibromo thiophene moiety32, which is reacted with a 2-mercaptoacetate to form theα,α′-bis(R-acyl)-β,β′-bis(carboxymethylthio)thiophene moiety 27.

Fused thiophene moieties having relatively large fused thiophene ringsystems can be synthesized using the reaction schemes described above.It is also possible to build large fused thiophene ring systems usingthe coupling and ring closure steps shown in the reaction scheme of FIG.6. A β-R-substituted-β′-bromo thiophene moiety 33, in which R is analkyl group, is used as the starting material in this scheme; syntheticroutes to 33 are described below. While in the reaction scheme of FIG.6, the β-R-substituted-β′-bromo thiophene moiety 33 is shown as having athieno[3,2-b]thiophene ring system, it may also have a monocyclicthiophene, or a larger fused thiophene ring system as described above atits core. The β-R-substituted-β′-bromo thiophene moiety 33 is lithiatedand reacted with sulfur bis(phenylsulfonate) (or sulfur dichloride) toform coupled thioether 34, which is lithiated and subjected to oxidativering closure using CuCl₂ to form the β,β″ disubstituted fused thiophenemoiety 35.

Polycyclic β-R-substituted-β′-bromo thiophene moieties can be made byperforming the reaction series of FIG. 2 on a β′-bromo thiophene moiety,as shown in the reaction scheme of FIG. 7. Tetrabromothiophene isdilithiated (selectively at the α-positions) and protonated to yielddibromothiophene 37, which is acylated (giving 38) and reacted with a2-mercaptoacetate to give α-(R-acyl)-β-carboxymethylthio-β′-bromothiophene moiety 39, which is cyclized and decarboxylated to yield 33.While the starting material in the reaction scheme of FIG. 7 is amonocyclic thiophene, polycyclic fused thiophene starting materials canbe used as well.

In another aspect, described herein are β-R-substituted-β′-bromothiophene compounds, in which R is an alkyl group as defined herein. Forexample, compounds described herein include those having structure 40,below. R can be, for example, an unsubstituted alkyl group.

The unsubstituted alkyl group according to this aspect can be astraight-chain alkyl group (e.g. butyl, pentyl, hexyl, heptyl, octyl,nonyl, decyl, undecyl, dodecyl or hexadecyl), a branched alkyl group(e.g. sec-butyl, neo-pentyl, 4-methylpentyl), or a substituted orunsubstituted cycloalkyl group (e.g. cyclopentyl, cyclohexyl). In oneaspect, R can be an alkyl group at least seven, at least eight, at leastnine, or at least ten carbons in size, which is substituted orunsubstituted. In one aspect, the substitution of the alkyl group isseparated from the fused thiophene ring system by at least two carbons.Examples of substituted alkyl groups according to this aspect include6-hydroxyhexyl and 3-phenylbutyl. The selection of R₁ and R₂ moietiesdepends upon the end use of the fused thiophene moiety-containingcomposition. Any functionality on the substituted alkyl group can beprotected in order to survive subsequent reaction steps. Unsubstitutedthiophene-based compositions tend to be relatively insoluble; as such,in one aspect, R can be an alkyl group having at least six carbons insize. For example, alkyl groups for improving solubility includeC_(k)H_(2k+1), where k is an integer greater than or equal to six.

In one aspect, compounds having structure 40 above can be synthesizedfrom β-R-substituted thiophene moieties by the bromination/debrominationmethod shown in FIG. 8. β-R-substituted thiophene 41 is fully brominatedwith molecular bromine to yield the trisbrominated compound 42, which isselectively lithiated and protonated at the α-positions to yield thedesired β-R-substituted-β′-bromo thiophene 40. The method of FIG. 8 canalso be used to make β-brominated fused thiophene moieties from fusedthiophene moieties. The monocyclic β-R-substituted-β′-bromo thiophene 40can be used to make tricyclic bis(R-substituted) fused thiophenemoieties according to the reaction scheme shown in FIG. 6. Themonocyclic β-R-substituted-β′-bromo thiophene 40 can also be used tomake monosubstituted fused thiophene moieties according to the reactionscheme shown in FIG. 9. For example, monocyclic thiophene 40 islithiated and reacted with formylpiperidine, and the adduct ishydrolyzed to yield aldehyde 43, which is reacted with a2-mercaptoacetate, cyclized and decarboxylated to yield β-R-substitutedfused thiophene 14.

In one aspect, any of the sulfur atoms present in the fused thiophenecompounds described herein can be oxidized to produce a SO₂ group. Inanother aspect, a composition includes at least one of the followingoxidized fused thiophene moieties:

In one aspect, with respect to structures 44 and 45, n is an integergreater than zero; m is no less than one; R₁ and R₂ are, independently,hydrogen or an alkyl group, wherein each T is, independently, S or SO₂,wherein T is SO₂ in at least one of the central-most rings of theoxidized fused thiophene ring system, and wherein when the fusedthiophene moiety has the formula 45, n is not 1. Each T is independentlyS and SO₂, where T is SO₂ in at least one of the central-most rings ofthe fused thiophene ring system. As used herein, the central-most ringof a fused thiophene ring system having an odd number 2q+1 of fusedrings is the q+1^(th) ring from an end of the ring system. Thecentral-most rings of a fused thiophene ring system having an evennumber 2q of fused rings are the q^(th) and q+1^(th) rings from an endof the ring system. For example, the central-most ring of a three-ringsystem is the second ring, the central-most rings of a four-ring systemare the second and third rings, and the central-most ring of a five-ringsystem is the third ring.

In another aspect, the oxidized moiety comprises the formula 44′ or 45′

wherein T is SO₂ in at least one of the central-most rings of theoxidized fused thiophene ring system. In one aspect, T in at least oneof the central-most rings is SO₂ and the remaining S atoms are notoxidized.

Any of the oxidized fused thiophene compounds described herein can beused in polymers, oligomers, monomers, chromophores, and othercompositions as described above. For example, the at least one oxidizedfused thiophene moiety can be present in the composition at a totalconcentration of at least 1 wt %. The value of n can be, for example, 1,2, 3, 4, or 5. In other aspects, the fused thiophene moiety is tricyclicor greater (i.e., 45′, n≧1; or 44′, n≧1). In further aspects, at leastone of R₁ and R₂ is an alkyl group at least six carbons in size directlybound to the oxidized fused thiophene ring system core of the oxidizedfused thiophene moiety. Both R₁ and R₂ can be alkyl groups, and can bethe same as or different from one another. In certain aspects, neitherR₁ nor R₂ is H. In other aspects, the composition has a ratio ofβ-hydrogen to oxidized fused thiophene ring systems of less than about1/10, 1/9, ⅛, 1/7, or ⅙. In one aspect, the oxidized fused compoundshave the structure

wherein n is an integer greater than zero; R₁ and R₂ are, independently,hydrogen or an alkyl group, and Q is, independently, hydrogen, asubstituted or unsubstituted alkyl group, an acyl halide, an ester, analdehyde, a ketone, a hydroxyl group, a thiol group or alkyl substitutedthiol group, an alkoxy group, an acrylate group, an amino group, a vinylether, a hydroxy alkyl group, a carboxylic acid group, or a halide.

The oxidized fused thiophene compounds described herein can beincorporated in a conjugated fused thiophene polymers or oligomershaving m>1. Alternatively, the oxidized fused thiophene compound can beincorporated in a polymer comprising a polyester, a polyurethane, apolyamide, a polyketone, a polyacrylate, a polymethacrylate, apolycarbonate, a polyether, or a poly(vinyl ether). It is contemplatedthat when the polymer comprises one or more moieties 44′ or 45′, n canbe greater than zero.

The oxidized fused thiophene compounds and moieties described herein canbe prepared by oxidation, for example, with MCPBA. Oxidation isgenerally selective at the central-most rings of the polycyclic fusedthiophene ring systems; however, it is contemplated that any of thesulfur atoms in the fused thiophenes can be oxidized. Examples ofoxidized fused thiophene moieties are shown below as structures 46, 47,48 and 49.

Fused thiophene and oxidized fused thiophene oligomers and polymers canbe prepared using methodologies similar to those used in making oligo-and poly(thiophenes) described above. For example, α,α′-dihydro fusedthiophene moieties can be oxidatively oligomerized or polymerized usingiron (III) compounds (e.g., FeCl₃, Fe(acac)₃), or can be brominated andcoupled in an organomagnesium mediated reaction. The fused thiophenemoieties and oxidized fused thiophene moieties described herein can beincorporated into other conjugated polymers such as, for examplephenylene, vinylene, and acetylene copolymers, using coupling reactionsfamiliar to the skilled artisan. The fused thiophene moieties andoxidized fused thiophene moieties described herein can be incorporatedinto other main chain and side chain polymers using techniques known inthe art. It is contemplated that the fused thiophene compound can beoxidized prior to incorporation into an oligomer or polymer. In thealternative, the fused thiophene compound can be incorporated into theoligomer or polymer followed by oxidation.

EXAMPLES

The following examples are put forth so as to provide those of ordinaryskill in the art with a complete disclosure and description of how thematerials, articles, and methods described and claimed herein are madeand evaluated, and are intended to be purely exemplary and are notintended to limit the scope of what the inventors regard as theirinvention. Efforts have been made to ensure accuracy with respect tonumbers (e.g., amounts, temperature, etc.) but some errors anddeviations should be accounted for. Unless indicated otherwise, partsare parts by weight, temperature is in ° C. or is at ambienttemperature, and pressure is at or near atmospheric. There are numerousvariations and combinations of reaction conditions, e.g., componentconcentrations, desired solvents, solvent mixtures, temperatures,pressures and other reaction ranges and conditions that can be used tooptimize the product purity and yield obtained from the describedprocess. Only reasonable and routine experimentation will be required tooptimize such process conditions.

Example 1 Di-β-substituted thieno[3,2-b]thiophenes

3,6-dihexylthieno[3,2-b]thiophene 57 was synthesized as shown in thereaction scheme of FIG. 10.

2,4,5-Tribromo-3-hexylthiophene (51). 3-Hexylthiophene (50) (100 g,0.595 mol) was mixed with 200 mL acetic acid. To this mixture, bromine(88 mL, 1.33 mol) was added dropwise. After addition of the bromine, theresulting mixture was stirred at room temperature for 4 hours, heated at60-70° C. overnight, then poured into 800 mL ice water and neutralizedwith 6M aqueous NaOH. The mixture was extracted with ethyl acetate(3×100 mL). The combined organic layers were washed with brine (2×100mL) and water (100 mL) and dried over MgSO₄. Evaporation of the solventyielded crude 51 (234 g, 97.1% crude yield). This crude product wassufficiently pure for use in subsequent reactions. GC/MS: 404 g/mol(M-1). ¹H NMR (CD₂Cl₂): δ 2.64 (t, 2H), 1.51 (m, 2H), 1.32 (m, 6H), 0.89(t, 3H). ¹³C NMR: 143.69, 117.86, 111.48, 110.18, 33.62, 32.86, 30.96,30.52, 24.70, 16.00.

3-Bromo-4-hexylthiophene (52). Compound 51 (70 g, 0.173 mol) was mixedwith dry THF (400 mL). To this mixture, n-butyllithium (138 mL, 2.5M inhexane, 0.345 mol) was added dropwise at −78° C. under argon. Theresulting mixture was stirred for 10 minutes, then water (30 mL) wasadded to quench the reaction. The THF was evaporated and the organic wasextracted with ethyl acetate (2×100 mL). The combined organic layerswere washed with brine (2×100 mL), water (70 mL) and dried over MgSO₄.After evaporation of the solvent, the resulting crude product waspurified by vacuum distillation (72-74° C. at 0.17 mbar) to yield 52(35.3 g, 82.6% yield). GC/MS: 246 g/mol (M-1). ¹H NMR (CD₂Cl₂): δ 7.22(s, 1H), 6.96 (s, 1H), 2.57 (t, 2H), 1.61 (m, 2H), 1.32 (m, 6H), 0.88(t, 3H). ¹³C NMR: 141.92, 122.87, 120.95, 112.89, 31.88, 30.07, 29.53,29.20, 22.88, 14.14.

1-(3-Bromo-4-hexyl-2-thienyl)heptanone (53). To a mixture of compound 52(24.7 g, 0.1 mol) and AlCl₃ (26.8 g, 0.2 mol) in dry CH₂Cl₂ (100 mL),heptanoyl (14.9 g, 0.1 mol) was added dropwise at room temperature. Thismixture was stirred for two hours, after which time GC/MS analysisindicated that a 3:1 mixture of target compound 53 and its regioisomer1-(4-bromo-3-hexyl-2-thienyl)heptanone (54) had been formed. Thereaction mixture was poured into 200 mL 6 M HCl and washed with water(3×50 mL). The organic layer was then dried over MgSO₄; evaporation ofthe solvent yielded 34.7 g of a crude mixture of compounds 53 and 54,which was used without separation or further purification in the nextreaction.

3,6-Dihexylthieno[3,2-b]thiophene-2-carboxylic acid (55). The mixture ofcompounds 53 and 54 (66.5 grams, 0.185 mol) was mixed with K₂CO₃ (53.6grams, 0.39 mol) and a catalytic amount of 18-crown-6 in 200 mL DMF. Tothis mixture, ethyl 2-mercaptoacetate (20.3 mL, 0.185 mol) was addeddropwise at 60-70° C. The reaction mixture was stirred at 60-70° C.overnight, then poured into water (800 mL). The organic component wasextracted with ethyl acetate (3×100 mL) and the combined organicextracts were washed with brine (2×100 mL) and water (100 mL). Thesolvent was removed by evaporation, and the residue was dissolved in THF(300 mL), forming a solution to which LiOH (84 mL, 10% solution inwater), MeOH (50 mL) and a catalytic amount of tetrabutylammonium iodidewere added. The mixture was heated at reflux for 3 hours, after whichtime the solvent was removed by evaporation, and the residue acidifiedwith concentrated HCl (50 mL). After dilution with 200 mL water, theorganic component was extracted with ethyl acetate (3×100 mL). Thecombined organic layers were washed with brine (2×100 mL), water (100mL) and dried over MgSO₄. After evaporation of the solvent, the compound55 was separated from unreacted compound 54 using column chromatography(SiO₂/5% ethyl acetate in hexane with 20% ethyl acetate in hexane tofully elute the compound 55), providing pure compound 55 (30 g, 46.1%yield). ¹H NMR (CD₂Cl₂): δ 7.24 (s, 1H), 3.18 (t, 2H), 2.73 (t, 2H),1.75 (m, 4H), 1.34 (m, 14H), 0.89 (m, 6H). ¹³C NMR: 169.15, 146.25,143.10, 141.49, 136.14, 126.67, 126.11, 31.99, 29.74 (6C), 22.99, 14.24.

3,6-Dihexylthieno[3,2-b]thiophene (57). A mixture of compound 55 (30 g,0.085 mol), copper powder (3.76 g) and quinoline (80 mL) was heated at264-260° C. in a Woods metal bath. When no further bubbles of carbondioxide gas could be detected (about 2 hours), the mixture was allowedto cool to room temperature and hexane (200 mL) was added. This mixturewas washed repeatedly with HCl (1-2 M in water) to remove the quinoline.The remaining organic layer was dried over MgSO₄ and concentrated byevaporation, leaving a residue, which was purified by columnchromatography (SiO₂/hexanes) to yield compound 57 (18 g, 68.4%). m.p.57.5-59.1° C., ¹H NMR (CD₂Cl₂): δ 6.97 (s, 2H), 2.70 (t, 4H), 1.73 (m,4H), 1.37 (m, 12H), 0.88 (t, 6H). ¹³C NMR: 136.56, 134.96, 109.80,31.94, 29.31, 29.28, 28.47, 22.96, 14.22.

The same reaction sequence was used to make3,6-didecylthieno[3,2-b]thiophene (58).

Example 2 Mono-β-substituted thieno[3,2-b]thiophenes

3-Hexylthieno[3,2-b]thiophene 58 was synthesized as shown in thereaction scheme of FIG. 11.

1-(3-Bromothienyl)heptanone (59). To a mixture of 3-bromothiophene (60)(16.3 g, 0.1 mol), AlCl₃ (26.8 g, 0.2 mol) and CH₂Cl₂ (100 mL),heptanoyl chloride (14.9 g, 0.1 mol) was added dropwise at roomtemperature. The resulting mixture was stirred for two hours after whichtime GC/MS indicated complete conversion of compound 60 to compound 59.The reaction mixture was poured into cold HCl (6M, 200 mL). The organiccomponent was extracted with hexane (3×100 mL). The combined organiclayers were washed with brine (2×100 mL) and water (100 mL). Afterdrying over MgSO₄, the crude target compound was purified by columnchromatography (SiO₂/hexanes) to yield compound 59 (25.1 g, 91.3%yield). GC/MS: 275 g/mol (M) ¹H NMR (CD₂Cl₂) δ 7.53 (d, 1H), 7.12 (d,1H), 3.01 (t, 2H), 1.71 (m, 2H), 1.38 (m, 6H), 0.92 (t, 3H).

Ethyl 3-hexylthieno[3,2-b]thiophene-2-carboxylate (61). Compound 59(35.4 g, 0.13 mol) and K₂CO₃ (27.6 g, 0.2 mol) were mixed withN,N-dimethylformamide (100 mL). A catalytic amount (˜25 mg) 18-crown-6was added, and to this mixture, ethyl 2-mercaptoacetate (14.0 mL, 0.13mol) was added dropwise at 60° C. The mixture was stirred overnight andpoured into water (500 mL). The organic component was extracted withethyl acetate (3×80 mL). The combined organic layers were washed withbrine (2×100 mL) and water (100 mL). Organic layer was then dried overMgSO₄. After evaporation of the solvent, the crude compound 61 wasobtained and purified by column chromatography (SiO₂/5% ethyl acetate inhexanes) to yield pure compound 61 (32.1 g, 84.5%). GC/MS: 296 g/mol(M). ¹H NMR (CD₂Cl₂) δ 7.56 (d, 1H), 7.24 (d, 1H), 4.34 (q, 2H), 3.15(t, 2H), 1.71 (m, 2H), 1.32 (m, 6H), 0.88 (m, 6H). ¹³C NMR: 163.24,143.31, 141.85, 141.09, 131.13, 128.44, 120.35, 61.25, 31.99, 29.72(overlap), 22.98, 14.52, 14.23.

3-Hexylthieno[3,2-b]thiophene-2-carboxylic acid (62). Compound 61 (32.1g, 0.11 mol) was mixed with LiOH (10% in water, 50 mL), THF (100 mL),MeOH (30 mL) and a catalytic amount (˜20 mg) tetrabutylammonium iodidein a 500 mL flask. This mixture was heated at reflux overnight, allowedto cool to room temperature, and acidified with concentrated HCl. Theresultant yellow solid was collected by filtration and washed thoroughlywith water. The solid then was heated with hexane (100 mL) allowed tocool to room temperature. After filtration, the solid was collected,dried over vacuum to yield compound 62 as a light yellow powder (28.0 g,96.7%). Mp: 110.7-112.4° C.

3-Hexylthieno[3,2-b]thiophene (58). A mixture of compound 62 (14.6 g,0.054 mol), copper powder (2.00 g), and quinoline (80 mL) was heated atabout 260° C. in a Woods metal bath. When no further bubbles of CO₂ weredetected (about 2 hours), the mixture was allowed to cool to roomtemperature, and hexane (200 mL) was added. The mixture was washedrepeatedly with HCL (1-2 M in water) to remove the quinoline. Theorganic layer was dried over MgSO₄ and concentrated by evaporation. Theresidue was purified by column chromatography (SiO₂/hexanes) to yieldcompound 58 (25.1 g, 90.3%). GC/MS: 224 g/mol (M). ¹H NMR (CD₂Cl₂) δ7.36 (m, 1H), 7.25 (m, 1H), 7.01 (m, 1H), 2.73 (t, 2H), 1.69 (m, 2H),1.34 (m, 6H), 0.89 (t, 3H). ¹³C NMR: 140.39, 139.13, 135.39, 127.01,122.19, 120.26, 32.01, 30.29, 29.43, 23.01, 14.24.

Example 3 Di-β-substituted dithieno[3,2-b:2′-3′-d]thiophenes anddi-β-substituted dithieno[3,2-b:2′-3′-d]thiophene-4,4-dioxides

3,6-didecylthieno[3,2-b]thiophene 63 and3,6-didecylthieno[3,2-b]thiophene-4,4-dioxide 64 were synthesized asshown in the reaction scheme of FIG. 12.

1,1′-(3,4-Bromo-2,5-thienyl)diundecanol (65). To a solution oftetrabromothiophene 36 (80.0 g, 0.2 mol) and THF (500 mL), butyllithium(160 mL, 0.4 mol, 2.5M in hexanes) was added dropwise at −78° C.Undecylic aldehyde (DecCHO) (69.7 g, 0.41 mol) was added, and thereaction mixture was stirred for two hours. The THF solvent was thenremoved by evaporation, and the organic residue was extracted withhexanes. The combined organic layers were washed by brine (2×100 mL) andwater (100 mL) and dried over MgSO₄. The crude product was purified bycolumn chromatography (SiO₂/5% ethyl acetate in hexanes) to yieldcompound 65 (84.1 grams, 72.5% yield). ¹H NMR (CD₂Cl₂) δ 5.02 (broad,2H), 1.79 (m 4H), 1.28 (m, 32H), 0.88 (t, 6H). ¹³C NMR: 143.25, 109.67,70.53, 38.31, 31.96, 29.75, 29.70, 29.61, 29.55, 29.21, 25.68, 22.84,14.09.

1,1′-(3,4-bromo-2,5-thienyl)diundecanone (66). A chromic acid solutionwas prepared by dissolving 100 grams of sodium dichromate dihydrate(0.34 mol) was in water (300 mL), then 136 grams of concentratedsulfuric acid was added, and the resulting solution was diluted to 500mL. Compound 65 (80.0 g, 0.137 mol) was mixed with acetone (300 mL). Tothis mixture, chromic acid solution (260 mL) was added dropwise at roomtemperature. The mixture was stirred overnight, after which timeconsiderable solid had formed in the reaction mixture. Most of theacetone was decanted and the rest of the mixture was extracted withethyl acetate (2×100 mL). The combined organic layers were washed withbrine (3×50 mL) and dried over MgSO₄. The solvent was evaporated, andthe residue was mixed with ethanol (100 mL) and white and pure compound66 solidified and was collected by filtration (72.0 g, 90.5% yield).M.p. 69.5-70.8° C. ¹H NMR (CD₂Cl₂) δ 3.07 (t, 4H), 1.74 (m, 4H), 1.28(m, 28H), 0.88 (t, 6H). ¹³C NMR: 192.49, 141.99, 118.82, 42.03, 32.13,29.79, 29.71, 29.62, 29.55, 29.29, 24.16, 22.92, 14.11.

Diethyl 3,5-didecyldithieno[3,2-b:2′,3′-d]thiophene-2,6-dicarboxylate(67). Compound 66 (30.0 g, 0.052 mol) was mixed with K₂CO₃ (28.7 g, 0.21mol) and N,N-dimethylformamide (100 mL). To this mixture, ethyl2-mercaptoacetate (11.5 mL, 0.104 mol) was added dropwise at 60° C. Thereaction mixture was stirred for 48 hours at 60° C. under nitrogen, thenwas poured into water (500 mL). The organic component was extracted withethyl acetate (3×100 mL). The combined organic layers were washed withbrine (2×100 mL) and water (50 mL) and dried over MgSO₄. The solvent wasevaporated, and the residue was purified by column chromatography(SiO₂/5% ethyl acetate in hexanes) to give compound 67 as sticky, lowmelting point solid (19.1 g, 59.3% yield). ¹H NMR (CD₂Cl₂) δ 4.36 (q.4H), 3.15 (t, 4H), 1.73 (m, 4H), 1.39 (m, 36H), 0.87 (m, 6H). ¹³C NMR:162.86, 145.47, 144.51, 133.05, 128.99, 61.63, 32.33, 29.99 (overlap),23.11, 14.53, 14.31.

3,5-Didecanyldithieno[3,2-b:2′,3′-d]thiophene-2,6-dicarboxylic acid(68). Compound 67 (10.2 g, 0.017 mol) was mixed with LiOH (1.0 g in 10mL water), THF (100 mL), MeOH (20 mL) and a catalytic amount (˜35 mg) oftetrabutylammonium iodide. This mixture was heated at reflux overnight,then most of the solvent was evaporated. The residue was acidified withconcentrated HCl (30 mL), forming a solid which was collected byfiltration, washed thoroughly with water, and vacuum dried to yieldcompound 68 (8.6 g, 98% yield). M.p. 280.1° C. ¹H NMR (CD₂Cl₂) δ 3.24(t, 4H), 1.72 (m, 2H), 1.29 (m, 30H), 0.88 (t, 6H). ¹³C NMR: 168.46,148.24, 146.58, 136.32, 35.91, 33.64, 28.91 (m, overlap), 26.60, 17.49.

3,5-Didecyldithieno[3,2-b:2′,3′-d]thiophene (63). Compound 68 (8.6 g,0.016 mol), copper powder (0.7 g) and quinoline (50 mL) were combinedand heated at 250-260° C. in a Woods-metal bath. When no further bubblesof carbon dioxide gas could be detected (about 2 hours), the mixture wascooled to room temperature and hexane (200 mL) was added. This mixturewas washed repeatedly with HCl (1-2 M in water) to remove quinoline. Theorganic layer was dried over MgSO₄ and concentrated by evaporation, andthe residue was purified by column chromatography (SiO₂/hexanes) toyield compound 63 (3.4 g, 47.4%). ¹H NMR (CD₂Cl₂) δ 6.97 (s, 2H), 2.73(t, 4H), 1.78 (m, 4H), 1.27 (m, 28H), 0.88 (t, 6H). ¹³C NMR: 141.89,136.75, 130.99, 120.57, 32.33, 30.02, 29.79 (m, overlap), 29.74, 29.15,23.10, 14.28.

Compounds 64 and 69 were prepared using the method described in Sogiu etal., Rigid-Core Fluorescent Oligothiophene-S,S-dioxide Isothiocyantes.Synthesis, Optical Characterization, and Conjugation to MonoclonalAntibodies, J. Org. Chem. 2003, 68, 1512-1520, which is incorporatedherein by reference.

3,5-Didecyldithieno[3,2-b:2′,3′-d]thiophene-4,4-dioxide (64).3-chloroperbenzoic acid (6.1 g, 0.035 mol), in 20 mL CH₂Cl₂ was addeddropwise to a solution of 63 (3.64 g, 8.18 mmol) in 20 mLdichloromethane. The mixture was stirred at room temperature overnight,then washing sequentially with 10% KOH, 10% NaHCO₃ and brine. Theorganic layer was dried over Mg₂SO₄, and the solvent was removed byevaporation. The crude product was purified by column chromatography(SiO₂/5% ethyl acetate in hexanes) to give compound 64 as a yellow solid(1.4 g, 35.9% yield). M.p. 58.7-60.3° C. ¹H NMR (CD₂Cl₂) δ 6.94 (s, 2H),2.73 (t, 4H), 1.72 (m, 4H), 1.27 (m, 28H), 0.88 (t, 6H). ¹³C NMR:142.99, 139.06, 136.36, 124.51, 32.27, 30.11, 29.95, 29.91, 29.68,29.48, 29.51, 28.51, 23.04, 14.22.

Diethyl3,5-didecyldithieno[3,2-b:2′,3′-d]thiophene-4,4-dioxide-2,6-dicarboxylate(69). 3-chloroperbenzoic acid (1.2 g, 6.9 mmol), in 20 mL CH₂Cl₂ wasadded dropwise to a solution of 67 (3.64 g, 8.18 mmol) in 20 mLdichloromethane. The mixture was stirred at room temperature overnight,then washing sequentially with 10% KOH, 10% NaHCO₃ and brine. Theorganic layer was dried over MgSO₄, and the solvent was removed byevaporation. The crude product was purified by column chromatography(SiO₂/5% ethyl acetate in hexanes) to give compound 69 as a waxy solid(0.56 g, 53% yield). ¹H NMR (CD₂Cl₂) δ 4.39 (q, 4H), 3.13 (t, 4H), 1.72(m, 4H), 1.27 (m, 34H), 0.88 (t, 6H). ¹³C NMR: 161.41, 145.52, 144.77,137.56, 132.89, 62.03, 32.11, 30.59, 29.82, 29.78, 29.75, 29.53, 29.49,27.88, 22.89, 14.21, 14.07.

The reaction scheme of FIG. 12 was also used to make3,5-dihexyldithieno[3,2-b:2′,3′-d]thiophene and3,5-dihexyldithieno[3,2-b:2′,3′-d]thiophene-4,4-dioxide.

Example 4 Di-β-substitutedthieno[3,2-b]thieno[2′,3′:4,5]thieno[2,3-d]thiophenes

3,7-Didecylthieno[3,2-b]thieno[2′,3′:4,5]thieno[2,3-d]thiophene 70 wassynthesized as shown in the reaction scheme of FIG. 13.

2,4-di(1-hydroxydecyl)-3,6-dibromothieno[3,2-b]thiophene (72).2,3,4,5-tetrabromothieno[3,2-b]thiophene (71) was prepared according toFuller et al., J. Chem. Soc., Perkin Trans, 1, 1997, 3465, which ishereby incorporated herein by reference. To a mixture of compound 71(40.0 g, 0.088 mol) in 300 mL dry THF, butyllithium (70 mL, 0.175 mol,2.5 M in hexanes) was added dropwise at −78° C. The resulting mixturewas stirred another 10 to 20 minutes and undecyl aldehyde (30.0 g, 0.176mol) was added dropwise. The mixture was allowed to warm to roomtemperature and stirred overnight. Water (20 mL) was added, and thesolvent was removed by evaporation. The residue was mixed with hexane(300 mL) and the resultant solid was collected by filtration. This solidthen was dried under vacuum, yielding compound 72 that was sufficientlypure for subsequent reaction (47.0 g, 83.9% yield). M.p. 116.0-118.0° C.¹H NMR (CD₂Cl₂) δ 5.15 (m, 2H), 2.31 (broad, 2H), 1.91 (m, 4H), 1.31 (m,32H), 0.92 (t, 6H). ¹³C NMR: 144.06, 109.05, 70.58, 38.77, 32.36, 30.06,30.04, 29.99, 29.77, 29.65, 26.09, 23.12, 14.29.

2,4-diundecanyl-3,6-dibromothieno[3,2-b]thiophene (73). Compound 72(30.0 g, 0.047 mol) was mixed with acetone (200 mL). To this mixture,chromic acid solution (130 mL) was added dropwise at room temperature.The mixture was stirred overnight at room temperature, after which timeconsiderable solid had formed in the reaction mixture. Most of theacetone was decanted and the rest of the mixture was extracted withethyl acetate (2×100 mL). The combined organic layers were washed withbrine (3×50 mL) and dried over MgSO₄. The solvent was evaporated, andthe residue was mixed with ethanol (100 mL) and white and pure compound73 solidified and was collected by filtration (18.4 g, 61.7% yield).M.p. 120.3-121.5° C. ¹H NMR (CD₂Cl₂) δ 3.09 (t, 4H), 1.78 (m, 4H), 1.28(m, 28H), 0.88 (t, 6H). ¹³C NMR: 193.15, 143.62, 143.40, 106.70, 41.74,32.12, 29.79, 29.72, 29.65, 29.55, 29.35, 24.20, 22.91, 14.11.

Diethyl 3,7-didecylthieno[3,2-b]thieno[2′,3′:4,5]thieno[2,3-d]thiophene2,6-dicarboxylate (74). Compound 73 was mixed with K₂CO₃ (16.6 g, 0.12mol) and N,N-dimethylformamide (100 mL). To this mixture, ethyl2-mercaptoacetate (6.6 mL, 0.06 mol) was added dropwise at 60° C. Thereaction mixture was stirred for 48 hours at 60° C. under nitrogen thenwas poured into water (500 mL). The resultant solid was collected byfiltration. The crude product was then boiled with ethanol (200 mL) andcooled to room temperature. Filtration and drying yielded compound 74(14.2 g, 72.4% yield). M.p. 130.5-132.2° C. ¹H NMR (CD₂Cl₂) δ 4.36 (q.4H), 3.15 (t, 4H), 1.73 (m, 4H), 1.27 (m, 34H), 0.87 (m, 6H). ¹³C NMR:163.09, 144.79, 144.29, 135.29, 134.28, 128.54, 61.83, 32.57, 30.32,30.26, 30.21, 30.07, 30.02, 29.98, 29.79, 23.33, 14.79, 14.49.

3,7-Didecylthieno[3,2-b]thieno[2′,3′:4,5]thieno[2,3-d]thiophene-2,6-dicarboxylicacid (75). Compound 74 (14.0 g, 0.021 mol) was mixed with LiOH (1.24 g,in 15 mL water), THF (100 mL), MeOH (20 mL) and a catalytic amount oftetrabutylammonium iodide. This mixture was heated at reflux overnightand most of the solvent was evaporated. The residue was acidified withconcentrated HCl (30 mL). The resultant solid was collected byfiltration, washed thoroughly with water and vacuum dried to yieldcompound 75 (12.5 g, 97.4% yield). M.p. 315.6-318.5° C.

3,7-didecylthieno[3,2-b]thieno[2′,3′:4,5]thieno[2,3-d]thiophene (70).Compound 75 (13.5 g, 0.021 mol) was mixed with copper powder (0.9 g) inquinoline (80 mL), and the mixture was heated to 250-260° C. in aWoods-metal bath. When no further bubbles of carbon dioxide gas could bedetected (about 2 hours), the mixture was allowed to cool to roomtemperature and hot hexane (400 mL) was added. This mixture was thenrepeatedly washed by HCl (2N, 4×50 mL). The hexane was partially removedby evaporation, and the resultant solid was collected by filtration andre-crystallized from hexane to afford compound 70 (7.0 g, 60.6% yield).M.p. 111.0-113.3° C. ¹H NMR (C₆D₆) δ 6.53 (s, 2H), 2.51 (t, 4H), 1.64(m, 4H), 1.27 (m, 28H), 0.89 (t, 6H). ¹³C NMR: 141.26, 136.42, 133.17,132.04, 120.73, 32.31, 30.03, 29.96, 29.90, 29.79, 29.66, 29.04, 23.07,14.28.

Example 5 Failed Attempt to Synthesize β-Substitutedthieno[2,3-d]thiophenes Using Conventional Coupling Reactions

The reaction scheme of FIG. 14 was followed in an unsuccessful attemptto synthesize β-hexyl-substituted thieno[2,3-d]thiophene. Because theelectronic properties of the fused ring systems are much different thanthose of a simple monocyclic thiophene, the coupling reactions used forthe monocyclic thiophenes did not work.

3,6-dibromothieno[3,2-b]thiophene (76, 5.2 g, 0.0175 mol) was dissolvedin dry diethyl ether (100 mL), and mixed with[1,3-bis(diphenylphosphino)propane]di-chloronickel(II) (dppp) (0.47 g,0.05 equivalents). To this solution hexylmagnesium bromide (22.0 mL of2.0 M solution in diethyl ether, 0.044 mol) was added dropwise. Theresulting mixture was heated at reflux for 24 hours. The reaction wasmonitored by GC/MS. After 24 hours, the starting material haddisappeared, but no Grignard addition product had been formed.

3-bromo-6-hexylthieno[3,2-b]thiophene (77, 6.2 g, 0.021 mol) wasdissolved in dry diethyl ether (100 mL) and mixed with[1,3-bis(diphenylphosphino)propane]di-chloronickel(II) (dppp) (0.51 g,0.05 equivalents). To this solution hexylmagnesium bromide (13.3 mL of2.0 M solution in diethyl ether, 0.027 mol) was added dropwise.

The resulting mixture was heated at reflux for 24 hours. The reactionwas monitored by GC/MS. After 6 hours, the starting material haddisappeared, but no Grignard addition product had been formed.

Example 6 Poly(β-substituted fused thiophenes)

Fused thiophene polymers were made using the general procedure describedbelow. This procedure is adapted from Andersson et al., Macromolecules1994, 27, 6506, which is incorporated herein by reference.

A monomeric α,α′-dihydro β,β′-dialkyl fused thiophene compound (10 mmol)was dissolved in 30 mL chlorobenzene. A suspension of ferric chloride(2.5 mmol) in 20 mL chlorobenzene was added to the monomer solution overhalf an hour. The mixture was allowed to stir for several (e.g. from 6to 24) hours at room temperature. It may be desirable to heat thereaction mixture at 80-90° C. for several hours for fused thiophenecompounds having larger (e.g. 4 or greater) numbers of rings in theirfused ring system. The reaction mixture was then precipitated from 500mL 95:5 methanol:water. The precipitate was collected by filtration,dissolved in toluene, boiled with concentrated ammonia (3×60 mL), andboiled with ethylenediaminetetraacetic acid (0.05 M in water, 2×50 mL).The organic layer was precipitated from methanol (500 mL); filtrationand vacuum drying (70-80° C.) yielded polymeric material.

Poly(3,6-dihexylthieno[2,3-d]thiophene) (35% yield);poly(3,6-didecylthieno[2,3-d]thiophene (90% yield);poly(3,7-didecylthieno[3,2-b]thieno[2′,3′:4,5]thieno[2,3-d]thiophene)(80% yield); andpoly(3,5-didecyldithieno[3,2-b:2′,3′-d]thiophene-4,4-dioxide) (43%yield) were prepared.

Example 7 Synthesis 2-2, 3-3 and 4-4 dimer and 5 and 7 ring systems

The synthesis 2-2, 3-3 and 4-4 dimers and 5 and 7 ring systems isdepicted in FIG. 15.

3,3′-dibromo-6,6′-didecanyl-2,2′-bisthienothiophene (82). To a flaskwith diisopropylamine (4.0 g, 0.039 mol) in dry THF (30 mL),butyllithium (2.5 M in hexane, 15.6 mL, 0.039 mol) was added dropwise at0° C. The resulting mixture was kept at 0° C. for 15 minutes.3-bromo-6-decanylthienythiophene (81) (14.0 g, 0.039 mol) was addeddropwise as a THF solution (30 mL). This mixture was stirred at 0° C.for one hour before cupper (II) chloride (6.3 g, 0.047 mol) was added.This dark brown solution was stirred for an additional 12 hours at roomtemperature. After evaporation all of the solvent, the residue wasboiled with toluene (200 mL), and the solid was filtered. The organicsolution was washed by brine (2×50 mL), water (50 mL) and dried overMgSO₄. After the toluene was evaporated, the residue was boiled withethanol (700 mL) and the solid was collected after cooling. The targetcompound was collected as a yellow solid crystal powder. Yielded 9.35 g(67%). Mp. 90.0-91.0° C. ¹HNMR: solvent CD₂Cl₂. δ: 7.15 (s, 2H), 2.74(t, 4H), 1.89-1.27 (m, 32H), 0.89 (t, 6H). ¹³CNMR: 140.78, 136.25,133.02, 131.65, 131.23, 120.47, 31.92, 29.61 (overlap), 29.36 (overlap),28.73, 22.69, 14.11.

3,6-didecanyl-dithieno[2,3-d:2′,3′-d′]thieno[3,2-b:4,5-b′]dithiophene(83). 3,3′-dibromo-6,6′-didecanyl-2,2′-bisthienothiophene (82) (8.6 g,0.012 mol) was dissolved into THF (100 mL). This solution was cooled to−78° C. under argon. To this solution, butyllithium (9.6 mL, 0.024 mol)was added dropwise, the resulting mixture was stirred for 30 minutes at−78° C. and bis(phenylsulfonyl)sulfide (3.8 g, 0.012 mol) was added.This solution was stirred overnight at room temperature before the THFwas evaporated. The residue was dissolved into hexane (300 mL) and theorganic layer was washed with brine (2×100 mL) and water (50 mL). Theorganic layer then was dried over MgSO₄. After evaporating the solvent,the crude product was purified by column chromatography (hot hexane) togive a solid compound. This yellow compound was recrystallized fromhexane, yielded 3.2 g (45.3%). Mp. 107.7-108.5° C. ¹HNMR: SolventCD₂Cl₂. δ, 7.024 (s, 2H), 2.76 (t, 4H), 1.79-1.28 (m, 32H), 0.88 (t,6H). ¹³CNMR: 140.58, 138.96, 135.94, 129.80, 122.86, 105.64, 31.92,29.77, 29.57, 29.33 (overlap), 28.69, 22.69, 14.11.

Referring to FIG. 15A, 83 can also be prepared by the cyclization of 87with butyllithium and copper chloride.

3,3′-dibromo-5,5′-didedecanyl-2,2′-bisdithieno[3,2-b:2′,3′-d]thiophene(85). To a flask with diisopropylamine (1.13 g, 0.011 mol) in dry THF(30 mL), butyllithium (2.5 M in hexane, 4.4 mL, 0.011 mol) was addeddropwise at 0° C. The resulting mixture was kept at 0° C. for 15minutes. 3-bromo-5-decanyl-dithieno[3,2-b:2′,3′-d]thiophene (84) (4.61g, 0.011 mol) was dissolved into THF (40 mL) and added dropwise. Thismixture was stirred at 0° C. for one hour before cupper (II) chloride(1.77 g, 0.013 mol) was added. This dark green solution was stirred foran additional 12 hours at room temperature. After evaporating all of thesolvent, the residue was boiled with toluene (2×100 mL) and the solidwas filtered. After evaporating all of the toluene, the residue wasboiled with toluene (200 mL) and cooled to room temperature. Crystallinesolid was collected after cooling. Yield 2.0 g. (43.8%). Mp.140.2-141.1° C. ¹HNMR: Solvent, CD₂Cl₂. ¹HNMR: δ 7.11 (s, 2H), 2.78 (t,4H), 1.75-1.28 (m, 32H), 0.86 (t, 6H).

3,7-didecanyl-bisdithieno{[3,2-b; 4,5-d][2′,3-b; 4′,5′-d]}thiophene(86). 3,3′-dibromo-5,5′-didecanyl-bisdithienothiophene (85) (3 g, 3.62mmol) was dissolved in dry tetrahydrofuran (80 mL) and cooled to −78° C.To this mixture, butyllithium (7.23 mmol, 2.9 mL) was added dropwiseunder argon. This resulting mixture was stirred at −78° C. for one hourbefore bis(phenylsulfonyl)sulfide (1.15 g, 3.62 mmol) was added througha solid addition funnel. The resulting mixture was stirred and slowlywarmed up to room temperature overnight. After evaporating the THF, theresidue was refluxed with water (200 mL) and filtered. The solid wasthen washed by methanol (2×50 mL) and refluxed with toluene (200 mL).The hot toluene solution was filtered to remove undissolved solid. Afterevaporating the toluene, the solid was re-dissolved into toluene (70 mL)and cooled to room temperature to produce brown-yellow needles of thetarget compound (1.68 g, 66.3%). Mp. 140.2-141.1° C. ¹HNMR solventCD₂Cl₂ δ 7.11 (s, 2H), 2.78 (t, 4H), 1.79-1.28 (m, 32H), 0.88 (t, 6H).

Referring to FIG. 15B, 86 can also be prepared by the cyclization of 88with butyllithium and copper chloride.

Example 8 Synthesis of tetraalkylsubstituted thienothiophene dimer

The synthesis of three-ring and four-ring tetraalkylsubstitutedthienothiophene dimers is depicted in FIGS. 16 and 17, respectively.

Three Ring Dimer

2-bromo-3-decanyldithieno[3,2-b:2′,3′-d]thiophene (92).3-decanyldithieno[3,2-b:2′,3′-d]thiophene (91) (9.03 g, 0.027 mol) wasdissolved in DMF (100 mL). To this solution, N-bromosuccinimide (NBS)(4.78 g, 0.027 mol) in DMF (50 mL) was added dropwise in the dark underargon. The resulting mixture was stirred at 0° C. for three hours. GC/MSshowed a single peak at 415. This solution was poured into water (500mL). Organic solution was extracted with hexane (3×100 mL). The combinedorganic solutions were washed with brine (2×50 mL) and water (50 mL).After drying over MgSO₄, the hexane was evaporated. The crude productwas purified by column chromatography and eluted with hexane to yieldthe target compound (10.1 g, 90.2%). ¹HNMR: solvent, CD₂Cl₂. δ 7.39 (d,1H), 7.29 (d, 1H), 2.74 (t, 2H), 1.74-1.33 (m, 16H), 0.89 (t, 3H).¹³CNMR: 140.89, 140.63, 136.00, 131.55, 129.22, 126.58, 121.04, 108.89,32.31, 29.94, 29.73 (overlap), 29.35, 28.49, 23.09, 14.27.

3-decanyl-6-dec-1-ynyldithieno[3,2-b:2′,3′-d]thiophene (93).2-bromo-3-decanyldithieno[3,2-b:2′,3′-d]thiophene (92) (4.16 g, 0.01mol) was mixed with 1-decyne (3.6 g, 0.026 mol),tetrakis(triphenylphosphine)palladium (0.58 g, 0.5 mmol) and copper(I)iodide (0.19 g, 1.0 mmol) in triethylamine (80 mL). This mixture wasbubbled with nitrogen for 5 minutes and then heated up to 130° C. underargon for 16 hours. Triethylamine was evaporated and hexane (150 mL) wasadded. This mixture was filtered to remove solid salts. The organiclayer was washed with 1 M hydrochloric acid (50 mL) and brine (50 mL)then dried over MgSO₄. The solvent was removed in vacuo, and the residuewas purified by chromatography on silica gel eluting with hexane toyield the target compound (3.87 g, 93.0%). ¹HNMR, solvent CD₂Cl₂. δ 7.36(d, 1H), 7.30 (d, 1H), 2.82 (t, 2H), 2.49 (t, 2H), 1.63-1.27 (m, 28H),0.88 (m, 6H).

2,3-didecanyldithieno[3,2-b:2′,3′-d]thiophene (94).3-decanyl-6-dec-1-ynyldithieno[3,2-b:2′,3′-d]thiophene (93) (36.0 g,0.076 mol) was dissolved into ethyl acetate (60 mL). To this solution,5% Pt/C (9.0 g) was added. The mixture was stirred under a H₂ atmosphere(90 psi) for 24 hours. The solution was then filtered. After removal ofthe ethyl acetate, the residue was purified by chromatography on silicagel eluted with hexane to produce the target compound (29.0 g, 79.9%).¹HNMR: solvent, CD₂Cl₂ δ 7.29 (d, 1H), 7.27 (d, 1H), 2.80 (t, 2H), 2.67(t, 2H), 1.68-1.27 (m, 32H), 0.88 (m, 6H). ¹³CNMR. 142.88, 140.75,139.82, 131.69, 131.37, 126.69, 125.04, 120.94, 32.16, 29.85 (m,overlap), 22.93, 14.11.

5,6,5′6′-tetradecanyl-2,2′-bisdithieno[3,2-b:2′,3′-d]thiophene (95). Toa hexane solution of 2,3-didecanyldithieno[3,2-b:2′,3′-d]thiophene (94)(5.16 g, 0.011 mol) and N,N,N′,N′,-tetramethylethylenediamine (TMEDA)(1.25 g, 0.011 mol), butyllithium (4.5 mL, 0.011 mol) was added dropwiseunder argon at room temperature. The resulting mixture was refluxed forone hour before copper (II) chloride powder was added to the reaction.This mixture was stirred overnight and hexane was removed in vacuo. Theresidue was boiled with toluene (80 mL) and the solid residue wasremoved by filtration. The organic layer was washed with brine (2×30 mL)and water (30 mL) and dried over MgSO₄. After removal of the toluene,the yellow solid was boiled with acetone (400 mL) and cooled to roomtemperature to produce crystalline target compound (1.26 g, 24.5%).¹HNMR: Solvent CD₂Cl₂. δ 7.43 (s, 2H), 2.89 (t, 4H), 2.73 (t, 4H),1.76-1.34 (m, 64H), 0.93 (m, 12H). ¹³CNMR: solvent C₆D₁₂. 143.28,141.09, 140.94, 138.12, 131.66, 131.41, 127.91, 117.18, 32.74, 32.63,30.44, 30.39, 30.32, 30.29, 30.13, 29.86, 28.58, 23.41, 14.25.

Referring to FIG. 16, 96 can also be prepared by the cyclization of 95with butyllithium and bis(phenylsulfonyl)sulfide.

Four Ring Dimer

2-Formyl-3-bromo-5decanyldithieno[3,2-b:2′,3′-d]thiophene (102). To aflask with diisopropylamine (2.76 g, 0.027 mol) in dry THF (100 mL),butyllithium (2.5 M in hexane, 10.9 mL, 0.0273 mol) was added dropwiseat 0° C. The resulting mixture was kept at 0° C. for 15 minutes.3-bromo-5-decanyl-dithieno[3,2-b:2′,3′-d]thiophene (101) (11.33 g,0.0273 mol) was dissolved into THF (60 mL) and added dropwise to thereaction. This mixture was kept at 0° C. for one hour before1-formylpiperidine was added. The resulting mixture was stirredovernight and THF was removed. The residue was washed with 10%hydrochloric acid (30 mL) and water (3×100 mL). The solid targetcompound was purified by crystallization from ethyl alcohol (100 mL).Yield 8.80 g (72.8%). Mp. 65.5-67.2° C.

2-carboxylic ethylester-5decanyldithieno[2,3-d:2′],3′-dithieno[3,2-b:4,5-b′]dithiophene(103). 2-Formyl-3-bromo-5-decanyldithieno[3,2-b:2′,3′-d]thiophene (102)(8.80 g, 0.02 mol) was dissolved into DMF (100 mL) and mixed withpotassium carbonate (9.66 g, 0.07 mol). A catalytic amount 18-crown-6ether was used as catalyst. To this solution, ethyl thioglycolate (2.52g, 0.021 mol) was added dropwise at 60-70° C. This mixture was stirredat this temperature overnight. After checking the GC/MS, the mixture waspoured into water (500 mL). The solid formed from the water solution wasremoved by filtration. The solid was then washed with water (2×200 mL)and methanol (200 mL). GC/MS showed a single peak at 465. After dryingin vacuo, the target compound was used without further purification.(8.0 g, 86%). Mp. 59.4-62.0° C.

2-carboxylicacid-5-decanyldithieno[2,3-d:2′,3′-d′]thieno[3,2-b:4,5-b′]dithiophene(104). 2-carboxylic ethylester-3-bromo-5decanyldithieno[2,3-d:2′,3′-d′]thieno[3,2-b:4,5-b′]dithiophene(103) (9.3 g, 0.02 mol) was dissolved in THF (100 mL). To this solution,methanol (20 mL) was added. LiOH (10% solution, 7 mL) was also added tothis mixture. A catalytic amount of tetrabutylammonium iodide was usedas catalyst. This mixture was refluxed overnight. After removal of ⅔ ofthe solvent, the residue was poured into concentrated HCl (100 mL). Thesolid was collected by filtration and washed with water until neutral.After drying, 6.06 grams of target compound was obtained (yield 69.3%).Mp. 225-227° C.

5-decanyldithieno[2,3-d:2′,3′-d]thieno[3,2-b:4,5-b]dithiophene (105).2-carboxylicacid-5-decanyldithieno[2,3-d:2′,3′-d′]thieno[3,2-b:4,5-b′]dithiophene(104) (6.06 g, 0.014 mol) was dissolved into quinoline (80 mL). Copperpowder (0.62 g, 9.7 mmol) was also added to this mixture. The mixturewas heated to 240-260° C. until no gas bubbles were observed (about onehour). The mixture was cooled to room temperature and poured into 30%HCl water solution (300 mL). The organic solution was extracted withhexane (150 mL) and washed with 10% HCl several times until quinolinewas removed from the organic layer. The organic layer was then driedover MgSO₄. After removing the solvent, the residue was recrystallizedfrom ethanol to produce 4.44 g of target compound (yield 81.3%). Mp.88.3-89.6° C. ¹HNMR. Solvent CD₂Cl₂. δ 7.38 (d, 1H), 7.32 (d, 1H), 6.99(m, 1H), 2.73 (t, 2H), 1.77 (m, 2H), 1.27 (m, 14H), 0.87 (t, 3H).¹³CNMR: 141.29, 140.59, 136.72, 133.51, 132.32, 132.27, 131.51, 126.29,121.15, 121.02, 32.32, 30.00, 29.96, 29.78 (overlap), 29.73, 29.11,23.09, 14.28.

2-Bromo-3-decanyldithieno[2,3-d:2′,3′-d′]thieno[3,2-b:4,5-b′]dithiophene(106). To5-decanyldithieno[2,3-d:2′,3′-d′]thieno[3,2-b:4,5-b′]dithiophene (105)(5.56 g, 0.0113 mol) in dry DMF (50 mL), NBS (2.01 g, 0.0113 mol) in DMF(30 mL) was added dropwise in the dark at 0° C. The resulting mixturewas stirred for two hours and poured into water (500 mL). The solid wasfiltered and washed by water several times. Ethanol (200 mL) was used torecrystallize the crude compound to give 5.06 g (94.9%). Mp. ¹HNMR:Solvent CD₂Cl₂. 7.43 (d, 1H), 7.34 (d, 1H), 2.77 (t, 2H), 1.74 (m, 2H),1.36-1.27 (m, 16H), 0.87 (t, 3H). ¹³CNMR: 140.87, 139.54, 135.98,133.31, 132.11, 131.70, 130.26, 126.77, 121.23, 109.03, 32.32, 29.99,29.92, 29.75. 29.66, 29.36, 28.50, 23.09, 14.28.

2-dec-1-ynyl-3-decanyldithieno[2,3-d:2′,3′-d′]thieno[3,2-b:4,5-b′]dithiophene(107).2-Bromo-3-decanyldithieno[2,3-d:2′,3′-d′]thieno[3,2-b:4,5-b′]dithiophene(2.16 g, 4.6 mmol) (106) was mixed with 1-decyne (1.27 g, 9.2 mmol),tetrakis(triphenylphosphine)palladium (0.27 g, 0.23 mmol) and copper(I)iodide (0.087 g, 0.46 mmol) in triethylamine (50 mL). This mixture wasbubbled with nitrogen for 5 minutes and then heated up to 130° C. underargon for 16 hours. The triethylamine was evaporated and hexane (150 mL)was added. This mixture was filtered to remove solid salts. The organiclayer was washed with 1 M hydrochloric acid (50 mL) and brine (50 mL),then dried over MgSO₄. The solvent was removed in vacuo, and the residuewas purified by chromatography on silica gel eluted with hexane toproduce the target compound (2.3 g, 90.2%). ¹HNMR: Solvent CD₂Cl₂. δ7.41 (d, 1H), 7.33 (d, 1H), 2.84 (t, 2H), 2.23 (t, 2H), 1.73-1.27 (m,28H), 0.89 (m, 6H).

2,3-didecanyldithieno[2,3-d:2′,3′-d′]thieno[3,2-b:4,5-b′]dithiophene(108).2-dec-1-ynyl-3-decanyldithieno[2,3-d:2′,3′-d′]thieno[3,2-b:4,5-b′]dithiophene(107) (2.2 g, 4.15 mmol) was dissolved into ethyl acetate (30 mL). Tothis solution, 5% Pt/C (0.5 g) was added. The mixture was stirred undera H₂ atmosphere (90 psi) for 24 hours. The solution was then filtered.After removal of the ethyl acetate, the residue was purified bychromatography on silica gel eluted with hexane to produce the targetcompound (2.00, 90.5%). Mp. 50.9-52.5° C. ¹HNMR: solvent, CD₂Cl₂ δ 7.41(d, 1H), 7.33 (d, 1H), 2.83 (t, 2H), 2.50 (t, 2H), 1.73-1.26 (m, 32H),0.87 (m, 6H). ¹³CNMR: 140.85, 140.40, 139.93, 133.38, 133.14, 132.22,129.69, 121.17, 120.09, 98.92, 32.29, 32.25, 29.99, 29.94, 29.72, 29.63,29.52, 29.33, 29.18, 29.06, 28.94, 23.05, 14.23.

Referring to FIG. 17, 109 can be prepared by coupling 108 withbutyllithium and copper chloride. The cyclization of 109 to produce 110can be accomplished by reacting 109 with butyllithium andbis(phenylsulfonyl)sulfide.

Example 9 Synthesis of Polymers Containing Fused Thiophene Moiety

Poly-3,6-dihexyl-thieno[3,2-b]thiophene(PDC6FT2) andPoly-3,6-didecanyl-thieno[3,2-b]thiophene(PDC10FT2). The monomer,3,6-dihexyl-thieno[3,2-b]thiophene (3.08 g, 0.01 mol) was dissolved intochlorobenzene. A suspension of FeCl₃ in chlorobenzene was added to themonomer solution within a half hour. The final concentration for themonomer and FeCl₃ was 0.05 and 0.2 M, respectively. The mixture wasstirred for 6-24 hours at room temperature. For larger ring sizes, themixture can be heated to 80-90° C. for several hours. The polymersolution was poured into 5% water methanol solution and a precipitateformed. The polymer was collected through filtration and re-dissolvedinto toluene. The toluene solution then was boiled with concentratedammonia (3×60 mL) and then boiled twice with ethylenediaminetetraaceticacid (EDTA) (0.05 M in water) (2×50 mL). The resulting toluene wasslowly added dropwise to methanol (500 mL) to precipitate polymer. Afterfiltration, the polymer was dried in vacuum oven (70-80° C.) overnight.Yields of PDC6FT2 and PDC10FT2 were 35% and 90%, respectively.

The method above was also used to produce the polymers PDC10FT4 (80%yield) and PDC10FTS3 (43% yield)

Example 10 Synthesis of Bithiophene and Fused Thiophene Copolymers

2,6-Dibromo-3,5-didecanyldithieno[3,2-b:2′3′-d]thiophene (1.0 g, 1.57mmol), 2,5′-distannyltrimethyl-bithiophene (0.772 g, 1.57 mmol) andtetrakis(triphenylphosphine)palladium(0) (0.095 g, 0.082 mmol) weredissolved in chlorobenzene (30 mL) under argon. The resulting mixturewas heated to 150° C. under argon for 14 hours before being precipitatedinto methanol (400 mL). The collected solid polymer was washed withacetone (100 mL) and extracted using acetone in a Soxhlet extractor. Thesolid polymer then was dissolved in chlorobenzene (100 mL) and filteredthrough a glass filter. After evaporating most of the chlorobenzene, thepolymer as shown below was precipitated from methanol (300 mL) again.The red polymer powder was dried under vacuum to give 0.9 grams (yield,90.1%).

2,7-Dibromo-3,6-didecanylpentathienoacene (0.89 g, 1.19 mmol),2,5′-distannyltrimethyl-bithiophene (0.59 g, 1.57 mmol) andtetrakis(triphenylphosphine)palladium(0) (0.072 g, 0.062 mmol) werereacted as described above. The polymer was extracted by hexane in aSoxhlet extractor. The final polymer as shown below was dried overvacuum to give 0.8 grams (yield, 89%).

2,8-Dibromo-3,7-didecanylthieno[3,2-b]thieno[2′,3′:4,5]thieno[2,3-d]thiophene (1.0 g, 1.45 mmol),1,4-ditrimethylstannylbenzene (0.59 g, 1.45 mmol) andtetrakis(triphenylphosphine)palladium(0) (0.084 g, 0.073 mmol) werereacted as described above. The polymer as shown below was dried undervacuum to give 0.82 grams (yield, 93.2%).

It will be apparent to those skilled in the art that variousmodifications and variations can be made to the present inventionwithout departing from the spirit and scope of the invention. Thus, itis intended that the present invention cover the modifications andvariations of this invention provided they come within the scope of theappended claims and their equivalents.

1. A composition comprising at least one moiety comprising the formula44′ or 45′

wherein n is an integer greater than one; m is no less than one; o is noless than one; x is greater than or equal to one; R₁ and R₂ are,independently, hydrogen or an alkyl group, wherein at least one of R₁and R₂ is an alkyl group, Ar is an aryl group, and T is S, SO, or SO₂,with the limitation that T is SO₂ in at least one of the central-mostrings of the oxidized fused thiophene ring system.
 2. The composition ofclaim 1, wherein T in the central-most ring is SO₂ and the remaining Satoms are not oxidized.
 3. A monomer, oligomer, or polymer comprisingthe moiety of claim
 1. 4. A polymer comprising a moiety comprising theformula 44′ or 45′

wherein n is an integer greater than one; m is no less than one; o is noless than one; x is greater than or equal to one; R₁ and R₂ are,independently, hydrogen or an alkyl group, wherein at least one of R₁and R₂ is an alkyl group, Ar is an aryl group, and T is S, SO, or SO₂,with the limitation that T is SO₂ in at least one of the central-mostrings of the oxidized fused thiophene ring system.
 5. The composition ofclaim 1, wherein both R₁ and R₂ are an alkyl group comprising at leastfour carbon atoms.
 6. The composition of claim 1, wherein R₁ and R₂ arethe same alkyl group.
 7. The composition of claim 1, wherein R₁ and R₂are different alkyl groups.
 8. The composition of claim 1, wherein R₁and R₂ are not hydrogen.
 9. The composition of claim 1, wherein n isfrom 2 to
 15. 10. The composition of claim 1, wherein n is 2, 3, or 4.11. The composition of claim 1, wherein the moiety comprises the formula200 or 201

wherein o is 1, 2, or 3, and R₃ and R₄ are, independently, hydrogen oran alkyl group.
 12. The composition of claim 11, wherein n is 2, 3, or4, and m is
 1. 13. The composition of claim 11, wherein n is 2, 3, or 4;m is one; and o is 1, 2, or
 3. 14. A monomer, oligomer, or polymercomprising the moiety of claim
 11. 15. The composition of claim 11,wherein Ar comprises one or more unfused thiophene groups, one or morefused thiophene groups, or a combination of unfused and fused thiophenegroups.
 16. The composition of claim 15, wherein the fused or unfusedthiophene groups are substituted or unsubstituted.
 17. A devicecomprising the composition of claim 1 configured in an electronic,optoelectronic, or nonlinear optical device.